Brake mechanism



E. R. EVANS.

BRAKE MEGHANISM Filed Dec. 18. 1922 s Shee ts-Sheer, 1

Sept. 1, I925. 1,551,871

Sept 1,1925.

L55L871 E.R.EVANS BRAKE MECHANISM Filed Dec. 18. 1922 s'sneets-sheet s w wm muuwwww bm Patented S e 1,

tain new and PATENT OFFICE.

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r H I V V a plicat on hammer 1a, 1922. Serial 30, 007,013.

To all whom it Be it 'known that I En R. EVANS, a citizen of the United t-ates ofAmerica, re-

sidin at Detroit, in the county of Wayne and gtate of have invented cerprovements in Brake Mechanisms, of which the following is a specification, reference being had therein to the accompanyingdrawings. I

This invention relates to brake mechanism for motor vehicles and relates particu .larly to mechanisms for establishing a common control over brakes'acting upon all 7 four wheels of a vehicle.

v It is theobject of thejnvention primaril to insure equaliiation of braking forces act ing on a plurality of vehicle wheels. Q

In the Figure 1 is a plan view of a motor vehicle chassis showing the improved brake mecha- Figure 2 is a view of the same side elevation; i

Figure 3 1s a cross section on line 3-3 of Figure 1 showing the provision forequalizingthe braking effort transmitted to the front wheels;

Figure 4 is a cross y, 1 a detail sectionalvieww'on line sectio n on line igure 5 is 55 of Figure 1 showing for equalizing the braklng effect upon-the rear wheels;

Figure 6 is a sectlon on line 6-6 'of'Fig- .I

ure 5. r

In theseviews the reference character A designates the frame of a motor vehicle and B the wheels thereof. Both the front and the rear wheels are provided with brake 'drums G. The particular. mechanism forflictionally gripping said drums is no feature of the present-invention and has not so. the frame A there are journalled front and been illustrated as :various forms of such mechanihmsare well known. D and D. are

pivotal arms for. respectively actuating Y the rakes 'of the front and rear wheels. E and E are pull rods respectively engaging said arms, said rods, extending from the front brakes" and forwardly from therear brakes. Upon the oentral portion of rear pairs of rock shafts F, F and G, G respectively, said shafts extending transversely of the frame. the outer Upon ends of the front shafts F, F at each side of the frameA depending arms H are asimilar provision ;ends of the rear rock-shafts G, G, and are intermeshed with a bevel'pinion J, said gears and pinion being enclosed within a naled: .Arms L and L project integrally downward from the casings K and K, the arm L-having a length considerably greater than that of the arm L, M is a pull rod 'forwardly extending from the arm L and hav-' ing pivotally secured to its front end a yoke N'in which journaled a sheave NM 0 is a flexible cable secured to a foot lever P a predetermined distance above the pivotal lower end P of said lever, said cable being rearwardly extending to thesheaye N, making a half turn arounds'aid sheave and extending forwardly from the sheave for attachment to the lower end of the arm L.

engaged y ca segmental bevel gears I "(l casing K upon which the pinion J is jour- In the operation of the described invn- I tion whem the foot lever P is forwardly;

rocked, the cable 0 transmits a forward pull to the rod M and a rearward pull to the arm L. The pull of the rod M acts through the 7 arm L to rock the rear casingK forwardly and the'front casing Ki is rearwardly rocked by the armlL; The'gears J and I form a means of communicating the rocking move- 7 ment of the casings K and K togthe'shafts, I

F, F and G, G" and equalization of the forees'acting upon the aligned shafts i's in- I sured by freedom of the gears J -to undergo yll llanetary travel with respectto the gears .I. 1

us the twotrainsof gearing J, I re-' spectively provide for equalization of the braking forces acting upon each of the front wheels and -each 'of the rear wheels. Fur- -is such as to equalize thef' forces acting upon the respective trains so that the-total braking force acting upon the front wheels will be equal to that acting'upon the rear ones; This equalization follows from the thermore the mechanism through which the brake force is transmitted to said-gear trains fact that thecable transmits its force in a predetermined definite ratio to the pull rod M and arm'L. The force acting upon the rod M will exceed that acting upon the arm L owing tovthe greater mechanical advantage under which the force is applied to said rod. Compensation is made, however, for this difference of forces by making the arm L longer to a predetermined extent than the arm L which said pull rod engaged. Thus the arrangement is such as to insure a perfect equalization of the forwardly and rearwardly transmitted braking forces. for the gearings I, J and casings K, K is in close proximity to one of the sills of the frame A, the rock shafts F and G have a sufficient length to extend substantially across said frame while the shafts F and G are comparatively short.

For emergency use the invention provides also a lever control for the front wheel brakes with aprovision for locking said brakes in said position. Thus R is a lever pivoted on a bracket R secured exteriorly to one of the sills of the frameA and S is a pull rod extending from an arm S on the shaft of said lever to the arm L and having a lost motion connection to the latter arm so that there will be no inter-' ference by said pull rod and lever with the control transmitted from the pedal P. Thus S is a longitudinal slot in the'forward end of the rod S and S is a pinupon the arm L engaging in the slot S When the pedal is actuated the slot S permits the pin S to move rearwardly without affecting the pull rod. Since, however, the pin normally occupies the forward end of the slot S the arm L will be immediately responsive to a rearward actuation of the lever. The bracket R rigidly carries a toothed sector T, the teeth of which are engageable by a pawl T to hold the lever B in brake setting position. T is a rod controlling the pawl T and T abutting upon the upper end of said rod for actuating the same.

The lever B provides for applying a brak ing force to the front wheels independently of the rear wheels and further permits looking of the front wheels under restraint of the brakes so that the vehicle may be prevented from accidental movement when in i said brakes, rock arms through which the front andrear pairs of brakes are respectively controlled, a cable transmitting control from-said actuating member to said rock Since the most convenient location ating member, and havin arms, and a sheave intermediately engaged by the cable transmitting control to one of said arms, the increased mechanical advantage gained by the arm actuated through said sheave being compensated for by giving the other arm a relatively great length.-

2.A brake mechanism comprising front and rear pairs of brakes, devices for equalizing the forces acting upon the brakes of each of said pairs, and a device for equalizing the total forces acting upon the front and rear pairs of brakes comprising a' cable transmitting the braking force to the front equalizing device, and a sheave intermediately engaged by said cable transmitting thebraking force to the rear device.

3. A brake mechanism comprising front and rear pairs ,of brakes, front and rear pairs, of rock shafts controlling said brakes,

versely of the vehicle, rock arms for respectively -actuating said pairs of rock shafts, means for equalizing the forces act ing upon the rock shaft from said arm, a rockable actuating member, a cable forming an actuating.- connection from said member to the forward rock arm, a tension member extending forwardly from A the rearmost rock arm, a sheave journaled at the forward end of' said tension member, said sheave being engaged by an intermediate portion of said cable.

4. A brake mechanism comprising front and rear pairs of brakes, devices for equaliz ing the braking force transmitted to' the brakes by each of said pairs, a pivotal member for actuating both pairs of brakes, and a cable having one end. connected to said pivotal member, and the other engaging one of said devices, a sheave intermediately en= gaging sald cable, and means connected to i said sheave-for actuating the other of said equalizing devices.

5. A- brake mechanism asset forth in claim 4, said sheave being adjustable through said cable longitudinally of the vehicle to izing .the braking forces applied to the.

brakes of each of said pairs, a flexible mem-, ber connected at one extremity to said actuits other extremity engaging one of said actuating devices, and a member intermediately engaged with said flexible member and having an actuating connection with the other equalizing device.

In testimony whereof I afiix my signature.

EDWIN R. EVANS. 

